visionMCP 👁️

The eyes of a bigger reasoning LLM.

visionMCP is a Model Context Protocol server that gives any MCP-capable agent real vision. A text-only reasoning model can delegate anything it cannot see to this server: describe a screenshot, answer a question about a photo, OCR a document, or compare two images — the server does the seeing and hands back text.

It works with all three major vision backends, chosen at runtime from a single config.json:

Features

• 🔍 Four vision tools for a reasoning LLM to call:

  • describe_image — full natural-language description

  • ask_about_image — targeted Q&A about any image

  • extract_text — OCR / transcription

  • compare_images — side-by-side comparison

• 🖼️ Every source accepted: local file paths, http(s) URLs, and base64 data: URIs.

• 📦 Zero image prep: oversized images are auto-downscaled and re-encoded as JPEG to fit provider payload limits.

• 🔌 Three transports: stdio (default, for local MCP clients), http (Streamable HTTP for remote hosting), or sse (legacy Server-Sent Events).

• ⚙️ One config.json controls provider, API key, API URL, and model. Environment variables and CLI flags can override anything.

• 🚀 uv-managed, installable, runnable, and hostable.

Related MCP server: vision-bridge-mcp

Quick start

1. Install

Requires uv and Python ≥ 3.10.

cd visionMCP
uv sync

2. Configure

The shipped config.json already works with a local Ollama. Switch providers by editing the file:

// config.json
{
  "provider": "openai",                  // "ollama" | "openai" | "anthropic"
  "api_key": "sk-...",                   // or leave "" and export OPENAI_API_KEY
  "api_url": "",                         // "" = provider default
  "model": ""                            // "" = provider default
}

See docs/configuration.md for every option, and docs/providers.md for per-provider setup.

Security: keep real API keys out of git — copy config.json to config.local.json (auto-ignored) or use environment variables. The server never logs your key.

3. Run

uv run vision-mcp                        # stdio transport (default)
uv run vision-mcp --transport http --host 0.0.0.0 --port 8100   # host remotely
uv run vision-mcp --show-config          # print resolved config (key masked)

Wiring into an MCP client

opencode (opencode.json)

{
  "mcpServers": {
    "visionMCP": {
      "type": "stdio",
      "command": "uv",
      "args": ["run", "--directory", "/absolute/path/to/visionMCP", "vision-mcp"]
    }
  }
}

Claude Desktop (claude_desktop_config.json)

{
  "mcpServers": {
    "visionMCP": {
      "command": "uv",
      "args": ["run", "--directory", "/absolute/path/to/visionMCP", "vision-mcp"]
    }
  }
}

Generic MCP client (stdio)

{
  "mcpServers": {
    "visionMCP": {
      "command": "/path/to/visionMCP/.venv/bin/vision-mcp",
      "args": ["--config", "/path/to/visionMCP/config.json"]
    }
  }
}

The server never sends image content to the vision API beyond what the tool call provides. Image bytes are kept in memory and never written to disk.

Tools reference

An image argument accepts any of:

/path/to/photo.png          # local file
https://example.com/x.jpg   # URL (downloaded at call time)
data:image/png;base64,iVBORw0KGgo...   # base64 data URI

How it works

Everything funnels through one function in src/vision_mcp/pipeline.py:

image (path / URL / data URI)  →  base64 + mime  →  vision model  →  text
        _read()                     _encode()         API[provider]    look()

The server tools are thin wrappers: pipeline.look(cfg, [image], prompt).

Documentation

• Configuration reference — every config option, env var, and precedence rules

• Provider setup — Ollama, OpenAI, and Anthropic, step by step

• Deployment — hosting over HTTP/SSE, Docker, hardening

Development

uv sync --group dev
uv run ruff check .
uv run pytest

License

MIT